Catalytic pyrolysis of mechanically non-recyclable waste plastics mixture: Kinetics and pyrolysis in laboratory-scale reactor.

Post-consumer waste plastics that cannot be mechanically recycled represent a concerning environmental issue. According to the latest available data for Europe, as much as 25% of collected post-consumer waste plastics are landfilled, 43% is energy recovered, and 32% is recycled. One possible way of recovering non-recyclable plastics is pyrolysis, which is considered environmentally friendly technology for obtaining fuel or chemicals from plastic waste. To tackle the challenge of recovering non-recyclable plastics via pyrolysis, it is necessary to determine their actual composition. Visual separation of collected non-recyclable plastics was performed, and Fourier-transform infrared spectroscopy was used to confirm the accuracy of visual separation. A significant amount of plastics labelled as "other" was found. Since the composition of "other" waste plastics has not been sufficiently investigated, relatively few studies on their pyrolysis have been conducted. Therefore, they were characterised and added to the mixture with other found polymer types of non-recyclable plastics. Thermogravimetric analysis was conducted to determine thermochemical behaviour and kinetic parameters required for laboratory pyrolysis investigation. Kinetic analysis was conducted using the Friedman isoconversional model-free method and non-linear multivariate regression method. The goal of this paper was to analyse the kinetics, determine the product yield and characteristics of the pyrolysis process of non-recyclable plastics over zeolite catalysts. It was found how the decomposition of non-recyclable plastics occurs in two decomposition steps. The activation energy of non-recyclable plastics was 144 kJ/mol in the first stage of decomposition and 262 kJ/mol in the second stage of decomposition. It decreased by 34% and 6.5% after fresh fluid catalytic cracking catalyst was added and 41% and 18.3% with iron-modified Zeolite Socony Mobil-5 catalyst. The yield of condensate was 55% (wax) for the original sample, and it decreased to 50% (wax and oil) and 27% (mostly oil) with fresh fluid catalytic cracking and iron modified Zeolite Socony Mobil-5 catalysts. Processes with catalysts promoted the formation of olefins and aromatic compounds in pyrolytic oil. All pyrolysis products had a high value of higher heating value ranging from 39 MJ/kg to 43 MJ/kg showing good potential for further energy use.

Effects of bioreactive acrolein from automotive exhaust gases on human cells in vitro.

Acrolein is a toxic unsaturated aldehyde and widespread environmental pollutant produced during lipid peroxidation and also by burning of tobacco or liquid fuels. Inhalation or dermal exposure to acrolein could be toxic to organisms. This very reactive aldehyde has a strong affinity for binding to proteins thus forming pathogenic protein-adducts. In the present study we have analyzed formation of bioreactive acrolein-protein adducts in bovine serum albumin solution exposed to exhaust gases of mineral diesel fuel and of mineral diesel fuel supplemented with different amounts of a novel diesel fuel additive denoted Ecodiesel (produced by a genuine procedure of recycling of plant oils used for food preparation). The effects of acrolein-protein adducts were tested on human microvascular endothelial cells and on human osteosarcoma cells that are sensitive to bioactivities of lipid peroxidation products. The results have shown a reduction of the bioreactive acrolein in exhaust gases when mineral diesel was supplemented with 5-20% Ecodiesel. Moreover, acrolein-protein adducts obtained from mineral diesel supplemented with Ecodiesel were less toxic than those obtained from mineral diesel alone. Thus, we assume that supplementing mineral diesel fuel with Ecodiesel would be of benefit for the use of renewable energy, for environment and for human health due to reduced environmental pollution with bioreactive acrolein.